Brantly was transported by a medical evacuation plane equipped with a containment unit, according to Samaritan’s Purse, an international relief organization. The plane landed at Dobbins Air Force Base near Atlanta on Saturday. Brantly was able to walk into the hospital, photographs appear to show.

A second patient, missionary Nancy Writebol, was expected to arrive in Atlanta on Tuesday, the Christian mission organization SIM said. She will be treated in the same Emory isolation unit. Writebol remained in serious but stable condition as of Monday, according to SIM.

“We are so grateful and encouraged to hear that Nancy’s condition remains stable and that she will be with us soon,” said Bruce Johnson, president of SIM USA, in a statement Monday. “Her husband, David, told me Sunday her appetite had improved and she requested one of her favorite dishes – Liberian potato soup – and coffee.”

Writebol, who works with SIM, was in Liberia on a joint team with Brantly of Samaritan's Purse.

Johnson says Writebol's husband will return to Atlanta on a separate flight and will stay in the area to be near her. Both Writebol and Brantly received a dose of an “experimental serum” before leaving Africa, Samaritan’s Purse said in a statement Sunday.

Initially, “there was only enough for one person. Dr. Brantly asked that it be given to Nancy Writebol,” said Franklin Graham, president of Samaritan’s Purse. But the organization said later Brantly was able to receive a dose of the serum as well. No further details were provided.